Import object in Rhino 4.0

Hello everyone!
I have a problem with editing an imported objects in rhino ! I just started using rhino4.0 in this PC and i cannot edit an imported object. I can open it and edit it alone (it is a mesh), but when I import it into another file it is selected only in the beginning. If I click to another point it cannot be selected again and I cannot understand why…Nothing is selected with the command Selall. I turned it also from mesh to nurbs but nothing changed. Does anyone have an idea why this is happening?

Thanks a lot!

Is the layer it’s on locked?

I cannot believe it was so simple… I feel so stupid! Thanks for opening my eyes!